Re: [PATCH] x86/numa: move setting parse numa node to num_add_memblk

From: Michal Hocko
Date: Wed Nov 29 2017 - 08:34:03 EST


On Wed 29-11-17 21:26:19, zhong jiang wrote:
> On 2017/11/29 21:01, Michal Hocko wrote:
> > On Wed 29-11-17 20:41:25, zhong jiang wrote:
> >> On 2017/11/29 20:03, Michal Hocko wrote:
> >>> On Wed 29-11-17 17:13:27, zhong jiang wrote:
> >>>> Currently, Arm64 and x86 use the common code wehn parsing numa node
> >>>> in a acpi way. The arm64 will set the parsed node in numa_add_memblk,
> >>>> but the x86 is not set in that , then it will result in the repeatly
> >>>> setting. And the parsed node maybe is unreasonable to the system.
> >>>>
> >>>> we would better not set it although it also still works. because the
> >>>> parsed node is unresonable. so we should skip related operate in this
> >>>> node. This patch just set node in various architecture individually.
> >>>> it is no functional change.
> >>> I really have hard time to understand what you try to say above. Could
> >>> you start by the problem description and then how you are addressing it?
> >> I am so sorry for that. I will make the issue clear.
> >>
> >> Arm64 get numa information through acpi. The code flow is as follows.
> >>
> >> arm64_acpi_numa_init
> >> acpi_parse_memory_affinity
> >> acpi_numa_memory_affinity_init
> >> numa_add_memblk(nid, start, end); //it will set node to numa_nodes_parsed successfully.
> >> node_set(node, numa_nodes_parsed); // numa_add_memblk had set that. it will repeat.
> >>
> >> the root cause is that X86 parse numa also go through above code. and arch-related
> >> numa_add_memblk is not set the parsed node to numa_nodes_parsed. it need
> >> additional node_set(node, numa_parsed) to handle. therefore, the issue will be introduced.
> >>
> > No it is not much more clear. I would have to go and re-study the whole
> > code flow to see what you mean here. So you could simply state what _the
> > issue_ is? How can user observe it and what are the consequences?
> The patch do not fix a real issue. it is a cleanup.
> because the acpi code is public, I find they are messy between
> Arch64 and X86 when parsing numa message . therefore, I try to
> make the code more clear between them.

So make this explicit in the changelog. Your previous wording sounded
like there is a _problem_ in the code.

--
Michal Hocko
SUSE Labs